The invention relates to a balancing device including a balancer provided with a shaft for clamping a wheel and a support structure with a bearing surface. The invention further relates to a balancing and inflation station having a balancing device of the type indicated and tire-changing apparatus with a bead breaking mechanism, a tire-changing mechanism and a balancing and inflation station of the type indicated.
The invention relates to a balancing device in accordance with the preamble of claim 1. The invention further relates to a balancing and inflation station having a balancing device of the type indicated and tire-changing apparatus with a bead breaking mechanism, a tire-changing mechanism and a balancing and inflation station of the type indicated.
A balancing device as indicated above is already known from EP 0 557 240 B1. The known balancing device represents an improvement over those devices in which the balancer cannot be pivoted and is only horizontally disposed, in that the occurrence of centering errors while the wheel is being clamped to the shaft of the balancer are precluded.
In practice, however, the known balancing device presents a number of disadvantages that can be attributed to the fact that, in the vertical centering position, the upper extremity of the balancer shaft projects relatively far over the bearing surface of the supporting structure. In order to mount a wheel on the balancer when it is pivoted into the centering position, the operator must lift the wheel relatively high, an operation associated with some difficulty, especially if the operator is not tall and the wheel rim is heavy.
Balancing devices of the type indicated above may also constitute a part of a balancing and inflation station and tire-changing equipment. A tire-changing device known in the art has the following functional units arranged sequentially:
1. a wheel elevator
2. a storage bench for multiple wheels
3. a bead breaker with turntable
4. a tire-changing device
5. an inflation station with inflation bench
6. a wheel-rotating system
7. a wheel hoist and
8. a balancing device.
With the known tire-changing equipment, the tire is changed in such a manner that the operator first drives the vehicle to the work area, where the vehicle is lifted; the wheels are then removed from the vehicle and are placed on the wheel elevator, which automatically lifts the wheels onto the storage bench. Once on the storage bench, the wheels are moved along the bench by tilting and rolling. A second operator changes the tire after releasing the rim bead with the bead breaker. To this end, the wheel is simply rolled from the storage bench to the bead breaker and then tipped onto the tire-changing machine. The wheel is then transported to the inflation station and inflated until a prescribed overpressure is reached. The tire is then deflated to achieve the correct final pressure. After inflation, the wheel is removed from the inflation bench by a further operator. To this end, the wheel is tilted onto the wheel hoist by a wheel rotating system situated adjacent to the inflation station. Here, the wheel is raised so that it can be clamped to the shaft of the balancer, which faces the inflation station, and the wheel is balanced thereupon.
Operation of the tire-changing equipment described above, in which a multiplicity of devices are combined, requires quite a large expenditure of effort, and, above all, the device itself takes up a great deal of space. The known tire-changing device is not suitable for use in smaller workshops.
The object of the invention is therefore to provide a balancing device of the type described in the introduction, which simplifies handling while a wheel is being clamped. If the balancing device is used in conjunction with a balancing and inflation station or tire-changing equipment, the object of the invention is also to provide a balancing and inflation station with the simplest and most compact design possible.
The objects described above with respect to a balancing device of the kind described in the introduction are essentially met according to the invention, in that the balancer is provided with a height adjustment mechanism so that the balancer can be lowered from the centering position into the supporting structure to the extent that the distal extremity of the shaft does not project above the bearing surface. The lowering capability of the balancer provided in accordance with the invention presents a number of significant advantages. First, it allows the balancer to be lowered completely, so that a wheel can be placed on the bearing surface or bench of the balancing device and then repositioned on the bearing surface or bench to assure the central opening of the wheel or rim is precisely centered on the shaft of the balancer. Appropriate centering means or devices may be provided on the bearing surface for this purpose. When the wheel has been positioned accordingly on the bearing surface of the balancing device, the balancer may be elevated from its lowered or retracted position, this operation causes the shaft to project through the rim opening and the wheel is consequently lifted. In any case, the wheel no longer has to be raised manually to the height of the balancer""s centering position.
The configuration according to the invention presents the further significant advantage that it is possible to integrate the balancing device in a combination balancing and inflation station. Besides the balancing device of the kind described, this station is also furnished with equipment for the supply of pressurized air and an inflation bench, wherein the bearing surface constitutes the inflation bench or the inflation bench serves as the bearing surface. The station according to the invention combines two distinct apparatuses of the known art, that is to say the inflation station and the balancing device, while rendering a wheel rotating system and a wheel hoist unnecessary, since inflation and balancing are performed at one and the same station. Thus, the space requirement of the balancing and inflation station and tire-changing equipment provided with such a station is also considerably reduced.
According to the invention, the tire of a wheel is changed in such a manner that when the old tire has been replaced by a new tire, the wheel is transported to the balancing and inflation station, and the wheel is placed on the inflation bench of the balancing and inflation station with the rim well facing downwards. The tire is inflated with air at a preset pressure. The wheel on the inflation bench is then clamped to the balancer shaft of the balancing and inflation station. For this purpose, the shaft is moved upwards with the balancer and into the centering position out of the balancing and inflation station. The balancer is then pivoted 90xc2x0 into the horizontal measuring position together with the wheel that is clamped to the shaft for the performance of the balancing measurement cycle. As can be seen, this method of inflation and balancing a wheel according to the invention differs markedly from the method known in the art.
The balancing device according to the invention is preferably furnished with at least one carriage guided by a guide, opposite which the balancer is pivotably arranged to allow rotation from the centering position to the measuring position and vice versa. In order to achieve uniform height adjustment, it may also be provided that the height adjustment mechanism is furnished with one guide having a carriage on each of the opposing sides, and the balancer is disposed between the carriages. The carriages are preferably connected to each other by means of a cross member, on which the balancer is pivotably disposed. Height adjustment of the balancer may be assured in all cases by electrical, pneumatic or hydraulic adjusting drives, such as electric motors as well as pneumatic or hydraulic cams.
In order to achieve a defined motion when pivoting the balancer, and to delimit the rotational travel, a preferred embodiment of the invention provides for pivoting to be effected by means of a cam plate and a spring-loaded pivot pin acting on the cam plate. The cam plate is further furnished with recesses at the extreme positions to engage with the pivot pin. In addition, limit stops are provided that prevent rotational travel significantly beyond the respective extreme position.
Additionally, in a preferred embodiment of the invention, the pivotable balancer is provided with braking means to slow the pivoting motion. Such braking means may have the form of counteracting cams.
In a particularly preferred configuration of the present invention, the height adjustment mechanism is provided with an articulated linkage that is pivotably disposed in the supporting structure and is connected at one end to the balancer and at the other end to the adjustment drive. The articulated linkage is constructed in such a manner that, upon actuation by means of the adjustment drive, it assures both elevating and pivoting motion of the balancer. A special angle lever and at least one further lever connected with the angle lever are provided specifically for this purpose.
The invention further relates to a balancing device having a balancer that is equipped with a shaft for clamping a wheel.
Balancing devices of the kind described above have long been known in the art. As a rule, the balancer in the known balancing devices is disposed together with the measurement electronics in a housing of the balancing device. The shaft of the balancer, to which the wheel is to be clamped for balancing, usually protrudes through a side wall of the housing of the balancing device. As part of the balancing operation, the wheel is placed on the horizontally extended shaft of the balancer.
However, a balancing device is also known, for example from EP 0 557 240 B1 cited in the introduction, in which the balancer is arranged pivotably in the balancing device, wherein the balancer can be pivoted from a top, centering position, in which the shaft of the balancer extends upwards, to the horizontal measuring position, in which the balancer shaft extends horizontally. The horizontal centering of the wheel to be balanced has the considerable advantage that the incidence of unbalanced masses as the wheel is being clamped to the shaft of the balancer, and the measurement errors resulting therefrom are minimized.
After the wheel has been clamped to the shaft of the balancer, the measurement cycle is performed. The balancer detects the magnitude and position of unbalanced masses. Balancer weights are applied to the rim in accordance with the unbalanced masses detected. The attachment of balancer weights inside the rim well of the wheel is usually difficult when using the known balancing devices: the operator has very little room in which to inspect the rim well when attaching the adhesive weights because of the wheel""s position parallel to the housing. The severe space limitations, and the fact that it is difficult and often impossible to see inside the rim well, may lead to incorrect positioning of the balancer weight in the rim well.
The object of the present invention is therefore also to provide a balancing device of the kind previously described, in which the adhesive balancer weights can be easily attached to the rim well in the correct position.
The object stated above is essentially met in accordance with the invention in that the balancer is pivotably arranged on a retaining arm of a supporting member in such manner that balancer may be pivoted 90xc2x0 downward from the horizontal measuring position, to a bottom fitting position. For the first time, the arrangement according to the invention allows the balancer weights to be attached inside the rim well with the wheel disposed horizontally. In the balancer""s bottom position, in which the shaft extends directly downwards, the rim well is now upwardly open, so that it is possible to view the rim well without any difficulty, and to attach the adhesive weight to the balance point that is clearly visible from the exterior.
In all cases, it is possible to arrange the longitudinal axis of the retaining arm coaxially or parallelly with the rotational axis of the shaft. In this case, the balancer is pivoted downwardly to the front, so that when in the fitting position the wheel being balanced is at least partly under the retaining arm. At least a part of the rim well of the wheel can still be seen from above without difficulty. However, in a preferred embodiment of the invention, the longitudinal axis of the retaining arm is not arranged coaxially or parallelly with the rotational axis of the shaft, but rather transversely thereto. This configuration not only provides the advantage that in the fitting position almost all areas of the rim well are visible from above, but also the transverse orientation of the balancer to the retaining arm makes it very simple to pivot the balancer upwardly through 90xc2x0 from the measuring position to the top position, the centering position. As was explained in the introduction, if the wheel is positioned and centered with the shaft in the vertical position, the incidence of measuring errors is very considerably reduced.
Of course, it is also possible in all cases to provide for pivoting motion of the balancer through a total of 180xc2x0 when longitudinal axis of the retaining arm is coaxially or parallelly arranged to the rotational axis of the shaft. In this case, the extremity of the retaining arm, on which the balancer is pivotably disposed, is forked, having at least one, but preferably two bearing arms.
The balancer can preferably be stopped in the centering position, the measuring position, and/or the fitting position. The stopping mechanism may be an easily releasable catch, or a positive locking arrangement. The balancer""s pivoting motion to the various positions may be effected by means of a cam plate in the manner previously described. The provision of appropriate limit stops also presents no difficulties.
In a particularly simple configuration of the present invention, in addition to the retaining arm, the supporting member is also furnished with a means for securing to a wall. Such a configuration is easily realized because the balancer can ultimately be a unit of very simple, compact construction that may be disposed without difficulty on one end of the retaining arm, while the wall attachment means is provided at the other end of the retaining arm. In this respect, in order to be able to sustain particularly large forces, it is advisable to conform the supporting member with a section designed for securing to a wall that is tangential to the retaining arm. The section for wall attachment may then be furnished with a plurality of securing flanges.
The section for wall attachment arranged perpendicularly to the retaining arm further offers the advantage that it is possible to construct the retaining arm so that it can pivot about the longitudinal axis of the wall attachment section. In this way, the retaining arm can be pivoted from its operating position, which is directed away from the wall, towards the wall so that the space requirement of the balancing device is extremely small.
Of course, instead of the previously described, extremely simple means for securing the balancing device of the invention to a wall, it is also possible to provide for such wherein the balancing device is furnished with a housing or supporting structure (substructure) of the kind previously described, in which the supporting member is housed. Such a device then represents a floor-mounted appliance, as is common in the prior art.
It should also be noted that the capability of pivoting as far as the fitting position described above may also be provided in all cases for a balancing device of the kind described in the introduction.